I have two Garhauer blocks for sale that can be used to improve the topping lift blocks that are suitable for either the 30' or 26' Nonsuch.   Used for only one season and are in like new condition.  With a 3/8" line, there is very little friction making topping lift adjustments very easy.  I'm selling these because I changed the configuration of the topping lift adjustment to move the block to the base of the mast and needed smaller blocks.

40-01 US (Stainless Steel) - Fiddle Block and 

40-02 US (Stainless Steel) - Fiddle Block with Becket and Shackle. 

I paid Garhauer $177 USD.   Your price $75 plus $10 shipping to anywhere in the US or Canada.

Links to the Garhauer web site that decribe the blocks:
https://www.garhauermarine.com/?s=40-01   and https://www.garhauermarine.com/?s=40-02